Just exercising a very minor subset of the functionality, but already proven useful.

v2: add missing locking v3: some more cleanup and consolidation, add unlocked test as well

Signed-off-by: Christian König christian.koenig@amd.com --- drivers/dma-buf/Makefile | 3 +- drivers/dma-buf/selftests.h | 1 + drivers/dma-buf/st-dma-resv.c | 282 ++++++++++++++++++++++++++++++++++ 3 files changed, 285 insertions(+), 1 deletion(-) create mode 100644 drivers/dma-buf/st-dma-resv.c

diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile index 1ef021273a06..511805dbeb75 100644 --- a/drivers/dma-buf/Makefile +++ b/drivers/dma-buf/Makefile @@ -11,6 +11,7 @@ obj-$(CONFIG_DMABUF_SYSFS_STATS) += dma-buf-sysfs-stats.o dmabuf_selftests-y := \ selftest.o \ st-dma-fence.o \ - st-dma-fence-chain.o + st-dma-fence-chain.o \ + st-dma-resv.o

obj-$(CONFIG_DMABUF_SELFTESTS) += dmabuf_selftests.o diff --git a/drivers/dma-buf/selftests.h b/drivers/dma-buf/selftests.h index bc8cea67bf1e..97d73aaa31da 100644 --- a/drivers/dma-buf/selftests.h +++ b/drivers/dma-buf/selftests.h @@ -12,3 +12,4 @@ selftest(sanitycheck, __sanitycheck__) /* keep first (igt selfcheck) */ selftest(dma_fence, dma_fence) selftest(dma_fence_chain, dma_fence_chain) +selftest(dma_resv, dma_resv) diff --git a/drivers/dma-buf/st-dma-resv.c b/drivers/dma-buf/st-dma-resv.c new file mode 100644 index 000000000000..50d3791ccb8c --- /dev/null +++ b/drivers/dma-buf/st-dma-resv.c @@ -0,0 +1,282 @@ +/* SPDX-License-Identifier: MIT */ + +/* +* Copyright © 2019 Intel Corporation +* Copyright © 2021 Advanced Micro Devices, Inc. +*/ + +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/dma-resv.h> + +#include "selftest.h" + +static struct spinlock fence_lock; + +static const char *fence_name(struct dma_fence *f) +{ + return "selftest"; +} + +static const struct dma_fence_ops fence_ops = { + .get_driver_name = fence_name, + .get_timeline_name = fence_name, +}; + +static struct dma_fence *alloc_fence(void) +{ + struct dma_fence *f; + + f = kmalloc(sizeof(*f), GFP_KERNEL); + if (!f) + return NULL; + + dma_fence_init(f, &fence_ops, &fence_lock, 0, 0); + return f; +} + +static int sanitycheck(void *arg) +{ + struct dma_resv resv; + struct dma_fence *f; + int r; + + f = alloc_fence(); + if (!f) + return -ENOMEM; + + dma_fence_signal(f); + dma_fence_put(f); + + dma_resv_init(&resv); + r = dma_resv_lock(&resv, NULL); + if (r) + pr_err("Resv locking failed\n"); + else + dma_resv_unlock(&resv); + dma_resv_fini(&resv); + return r; +} + +static int test_signaling(void *arg, bool shared) +{ + struct dma_resv resv; + struct dma_fence *f; + int r; + + f = alloc_fence(); + if (!f) + return -ENOMEM; + + dma_resv_init(&resv); + r = dma_resv_lock(&resv, NULL); + if (r) { + pr_err("Resv locking failed\n"); + goto err_free; + } + + if (shared) { + r = dma_resv_reserve_shared(&resv, 1); + if (r) { + pr_err("Resv shared slot allocation failed\n"); + goto err_unlock; + } + + dma_resv_add_shared_fence(&resv, f); + } else { + dma_resv_add_excl_fence(&resv, f); + } + + if (dma_resv_test_signaled(&resv, shared)) { + pr_err("Resv unexpectedly signaled\n"); + r = -EINVAL; + goto err_unlock; + } + dma_fence_signal(f); + if (!dma_resv_test_signaled(&resv, shared)) { + pr_err("Resv not reporting signaled\n"); + r = -EINVAL; + goto err_unlock; + } +err_unlock: + dma_resv_unlock(&resv); +err_free: + dma_resv_fini(&resv); + dma_fence_put(f); + return r; +} + +static int test_excl_signaling(void *arg) +{ + return test_signaling(arg, false); +} + +static int test_shared_signaling(void *arg) +{ + return test_signaling(arg, true); +} + +static int test_for_each(void *arg, bool shared) +{ + struct dma_resv_iter cursor; + struct dma_fence *f, *fence; + struct dma_resv resv; + int r; + + f = alloc_fence(); + if (!f) + return -ENOMEM; + + dma_resv_init(&resv); + r = dma_resv_lock(&resv, NULL); + if (r) { + pr_err("Resv locking failed\n"); + goto err_free; + } + + if (shared) { + r = dma_resv_reserve_shared(&resv, 1); + if (r) { + pr_err("Resv shared slot allocation failed\n"); + goto err_unlock; + } + + dma_resv_add_shared_fence(&resv, f); + } else { + dma_resv_add_excl_fence(&resv, f); + } + + r = -ENOENT; + dma_resv_for_each_fence(&cursor, &resv, shared, fence) { + if (!r) { + pr_err("More than one fence found\n"); + r = -EINVAL; + goto err_unlock; + } + if (f != fence) { + pr_err("Unexpected fence\n"); + r = -EINVAL; + goto err_unlock; + } + if (dma_resv_iter_is_exclusive(&cursor) != !shared) { + pr_err("Unexpected fence usage\n"); + r = -EINVAL; + goto err_unlock; + } + r = 0; + } + if (r) { + pr_err("No fence found\n"); + goto err_unlock; + } + dma_fence_signal(f); +err_unlock: + dma_resv_unlock(&resv); +err_free: + dma_resv_fini(&resv); + dma_fence_put(f); + return r; +} + +static int test_excl_for_each(void *arg) +{ + return test_for_each(arg, false); +} + +static int test_shared_for_each(void *arg) +{ + return test_for_each(arg, false); +} + +static int test_for_each_unlocked(void *arg, bool shared) +{ + struct dma_resv_iter cursor; + struct dma_fence *f, *fence; + struct dma_resv resv; + int r; + + f = alloc_fence(); + if (!f) + return -ENOMEM; + + dma_resv_init(&resv); + r = dma_resv_lock(&resv, NULL); + if (r) { + pr_err("Resv locking failed\n"); + goto err_free; + } + + if (shared) { + r = dma_resv_reserve_shared(&resv, 1); + if (r) { + pr_err("Resv shared slot allocation failed\n"); + dma_resv_unlock(&resv); + goto err_free; + } + + dma_resv_add_shared_fence(&resv, f); + } else { + dma_resv_add_excl_fence(&resv, f); + } + dma_resv_unlock(&resv); + + r = -ENOENT; + dma_resv_iter_begin(&cursor, &resv, shared); + dma_resv_for_each_fence_unlocked(&cursor, fence) { + if (!r) { + dma_resv_iter_end(&cursor); + pr_err("More than one fence found\n"); + r = -EINVAL; + goto err_free; + } + if (f != fence) { + dma_resv_iter_end(&cursor); + pr_err("Unexpected fence\n"); + r = -EINVAL; + goto err_free; + } + if (dma_resv_iter_is_exclusive(&cursor) != !shared) { + dma_resv_iter_end(&cursor); + pr_err("Unexpected fence usage\n"); + r = -EINVAL; + goto err_free; + } + r = 0; + } + dma_resv_iter_end(&cursor); + if (r) { + pr_err("No fence found\n"); + goto err_free; + } + dma_fence_signal(f); +err_free: + dma_resv_fini(&resv); + dma_fence_put(f); + return r; +} + +static int test_excl_for_each_unlocked(void *arg) +{ + return test_for_each_unlocked(arg, false); +} + +static int test_shared_for_each_unlocked(void *arg) +{ + return test_for_each_unlocked(arg, true); +} + +int dma_resv(void) +{ + static const struct subtest tests[] = { + SUBTEST(sanitycheck), + SUBTEST(test_excl_signaling), + SUBTEST(test_shared_signaling), + SUBTEST(test_excl_for_each), + SUBTEST(test_shared_for_each), + SUBTEST(test_excl_for_each_unlocked), + SUBTEST(test_shared_for_each_unlocked), + }; + + spin_lock_init(&fence_lock); + return subtests(tests, NULL); +}

On 06/10/2021 13:36, Christian König wrote:

A simpler version of the iterator to be used when the dma_resv object is locked.

v2: fix index check here as well v3: minor coding improvement, some documentation cleanup

Signed-off-by: Christian König christian.koenig@amd.com

drivers/dma-buf/dma-resv.c | 51 ++++++++++++++++++++++++++++++++++++++ include/linux/dma-resv.h | 20 +++++++++++++++ 2 files changed, 71 insertions(+)

diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c index a480af9581bd..2f98caa68ae5 100644 --- a/drivers/dma-buf/dma-resv.c +++ b/drivers/dma-buf/dma-resv.c @@ -423,6 +423,57 @@ struct dma_fence *dma_resv_iter_next_unlocked(struct dma_resv_iter *cursor) } EXPORT_SYMBOL(dma_resv_iter_next_unlocked);

+/**

• • dma_resv_iter_first - first fence from a locked dma_resv object
• • @cursor: cursor to record the current position
• • Return the first fence in the dma_resv object while holding the
• • &dma_resv.lock.
• */

+struct dma_fence *dma_resv_iter_first(struct dma_resv_iter *cursor) +{

• struct dma_fence *fence;
• dma_resv_assert_held(cursor->obj);
• cursor->index = 0;
• if (cursor->all_fences)

• cursor->fences = dma_resv_shared_list(cursor->obj);
  

• else

• cursor->fences = NULL;
  

• fence = dma_resv_excl_fence(cursor->obj);
• if (!fence)

• fence = dma_resv_iter_next(cursor);
  

• cursor->is_restarted = true;
• return fence;

+} +EXPORT_SYMBOL_GPL(dma_resv_iter_first);

+/**

• • dma_resv_iter_next - next fence from a locked dma_resv object
• • @cursor: cursor to record the current position
• • Return the next fences from the dma_resv object while holding the
• • &dma_resv.lock.
• */

+struct dma_fence *dma_resv_iter_next(struct dma_resv_iter *cursor) +{

• unsigned int idx;
• dma_resv_assert_held(cursor->obj);
• cursor->is_restarted = false;
• if (!cursor->fences || cursor->index >= cursor->fences->shared_count)

• return NULL;
  

• idx = cursor->index++;
• return rcu_dereference_protected(cursor->fences->shared[idx],

• 			 dma_resv_held(cursor->obj));
  

+} +EXPORT_SYMBOL_GPL(dma_resv_iter_next);

• /**
  • dma_resv_copy_fences - Copy all fences from src to dst.
  • @dst: the destination reservation object

diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h index 764138ad8583..491359cea54c 100644 --- a/include/linux/dma-resv.h +++ b/include/linux/dma-resv.h @@ -179,6 +179,8 @@ struct dma_resv_iter {

struct dma_fence *dma_resv_iter_first_unlocked(struct dma_resv_iter *cursor); struct dma_fence *dma_resv_iter_next_unlocked(struct dma_resv_iter *cursor); +struct dma_fence *dma_resv_iter_first(struct dma_resv_iter *cursor); +struct dma_fence *dma_resv_iter_next(struct dma_resv_iter *cursor);

/**

• dma_resv_iter_begin - initialize a dma_resv_iter object

@@ -244,6 +246,24 @@ static inline bool dma_resv_iter_is_restarted(struct dma_resv_iter *cursor) for (fence = dma_resv_iter_first_unlocked(cursor); \ fence; fence = dma_resv_iter_next_unlocked(cursor))

+/**

• • dma_resv_for_each_fence - fence iterator
• • @cursor: a struct dma_resv_iter pointer
• • @obj: a dma_resv object pointer
• • @all_fences: true if all fences should be returned
• • @fence: the current fence
• • Iterate over the fences in a struct dma_resv object while holding the
• • &dma_resv.lock. @all_fences controls if the shared fences are returned as
• • well. The cursor initialisation is part of the iterator and the fence stays
• • valid as long as the lock is held and so no extra reference to the fence is
• • taken.
• */

+#define dma_resv_for_each_fence(cursor, obj, all_fences, fence) \

• for (dma_resv_iter_begin(cursor, obj, all_fences), \

•     fence = dma_resv_iter_first(cursor); fence;	\
  

•     fence = dma_resv_iter_next(cursor))
  

• #define dma_resv_held(obj) lockdep_is_held(&(obj)->lock.base) #define dma_resv_assert_held(obj) lockdep_assert_held(&(obj)->lock.base)

Reviewed-by: Tvrtko Ursulin tvrtko.ursulin@intel.com

Regards,

Tvrtko